Figure 3. Ligation of TLR7 on DCs promotes CD4⁺T cells proliferation.

(A) Naïve CD4⁺CD25⁻T cells, CD4⁺CD25⁺Treg cells or DCs were first cultured in the presence or absence of TLR7 ligand Loxoribin, and the direct effect of Loxoribin on the T cell proliferation ex vivo was determined by incorporation of tritiated thymidine. Then, CD4⁺CD25⁻T cells or CD4⁺CD25⁺Tregs co-cultured with DCs in the presence of Loxoribin, and the effect of Loxoribin on T cell proliferation was determined. (B) CD4⁺CD25⁻T cells, CD4⁺CD25⁺Treg or DCs were purified from both wild-type and TLR7−/− mice, and then co-cultured with different combinations of either wild-type or TLR7−/− T cell subsets in the presence of wild-type or irradiated TLR7−/−DCs, the effect of Loxoribin on the T cell proliferation was determined by incorporation of tritiated thymidine. Data are representative of three independent experiments. *P < 0.05.